Test time hyper-parameters. Following  [1]}, we set hyper-parameters in testing as follows: threshold of non-maximum suppression in the roi head is set as 0.7 (0.5 by default) and, in the region proposal network, the number of region proposals kept after the suppression is set as 2000 (1000 by default). Table  REF  shows the performance difference by the hyper-parameters. AP tends to improve by decreasing the threshold value and degrade by increasing the number of proposals. Low threshold suppresses more boxes, which results in improving AP and degrading AR. Changing the number of proposals has a similar effect. We can observe that the difference is not significant.
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